After the bulk tungsten (W) deposition and subsequent W CMP step, the W overburden is removed, leaving the underlying Ti/TiN barrier layer exposed on the field dielectric A2.The Ti/TiN stack serves as an essential diffusion barrier and adhesion promoter between the W plug and the interlayer dielectric (ILD) P1.The TiN/Ti CMP step is required to completely remove this remaining field barrier layer, physically and electrically isolating the individual W contacts before the subsequent Metal 0 proce